During start-up of an integrated circuit, it may be necessary for some of the analog and digital circuitry to function while the power supplies are ramping up. For example, it may be required to access registers for example in one-time programmable (OTP) memory. OTP memory and control logic includes analog and digital circuitry which must perform reliably during the start-up phase of the integrated circuit. Reliable operation of digital circuitry often requires the use of a power-on-reset circuit. The power-on-reset circuit typically generates a signal that typically asynchronously resets the flipflops in a digital core. The digital logic is reset before the supply voltage level reaches the final value. A power supply ready indicator circuit may also be used to indicate that the power supply is ready for the analog circuits to operate. The power supply ready indicator circuit is implemented using similar circuitry to the power-on-reset and also triggers before the supply voltage reaches the final value.